In known apparatuses of this type, the input device is conventionally formed by an operating instrument with an operating face, on which buttons for adjusting the various segments are arranged. For this purpose, typically, in addition to the buttons for adjusting the individual segments, pictographs of the bed are depicted in a side view, the respective segment being emphasized in colour in these pictographs. By means of the pictographs, the user recognizes the button provided for adjusting a specific segment.
When a patient is supported on the bed in the usual way, that is to say in what is known as a normal position, each of the segments of the bed matches with a specific body part or body portion. For example, the bed may comprise a back segment, as a result of the adjustment of which the back is raised or lowered in the patient's normal position, etc.
In practice, however, the situation arises where patients are supported on the bed differently from the normal position. An important instance is a support which deviates from the normal position and in which the patient is displaced in the direction of the head end or foot end in relation to the normal position. There may be various reasons for such a support which deviates from the normal position. For example, it may be necessary, for a special intervention, that additional medical instruments, for example an operating microscope, have to be brought into the vicinity of a body part to be treated, and that this cannot be done for reasons of space when the patient is supported in the normal position. Another reason may be that a specific body part is to be radiographed, lying on the operating table, and that this is not possible in the normal position. However, supports deviating from the normal position may also become necessary due to specific operating techniques, novel interventions, anatomical features or a surgeon's preference.
A further example of a support deviating from the normal position is what is known as “reverse support”, in which the patient is rotated through 180° in relation to the normal position such that the head and foot end are interchanged. Even a reverse support of this kind may be necessary for reasons of space. However, it is also used relatively frequently, for example, in neurological operations in the head region.
When the patient is supported on the bed in a position other than the normal position, the following problem arises: since, in the position deviating from the normal position, the patient's body parts lie at least partially on other segments of the bed than in the normal position, as a rule, to adjust a specific body part, other segments of the bed have to be adjusted than those in the normal position. The user must therefore always consider which of the segments has to be adjusted, in the present position of the patient on the bed, in order to vary the position of a specific body part. This “rethink” between the various positions of the patient on the bed places an additional burden on the user, that is to say the surgeon or the theatre sister, and errors may occur during adjustment.
The correct adjustment of the bed may, in practice, be made even more difficult when the view of the bed is disguised by cover sheets or appliances, so that the user cannot see which segment has to be adjusted in order to vary the position of a body part. A further difficulty is that the beds of modern operating tables are often asymmetric, so that the illustrations of the pictographs identifying the buttons of the operating instrument correctly reproduce only the view from one side, but not the view from the other side. If the user stays on this other side of the operating table, this additionally complicates the choice of the correct button.